Automated clutches or clutches operated by an actuator are increasingly used in modern motor vehicles, both in conjunction with manual transmissions and in conjunction with automatic gears. Due to the elasticities contained in it, the drive train of a motor vehicle can be excited into oscillations that unpleasantly impair driving comfort.
WO 2004/027285 A1 discloses a method for the reduction of clutch-grabbing oscillations of the drive train whereby such clutch-grabbing oscillations occur primarily during the engagement of the clutch when starting up or after a gear change. The torque that can be transmitted by the clutch and/or the clutch travel can be so modulated in the process that the clutch-grabbing oscillations are counteracted. The required travel of an operating member of the clutch is modulated in an additive fashion, something that results in a modulation of the actual adjustment travel of the operating member and thus to a modulation of the transmissible clutch moment. Effective advance phase control can be accomplished in case the positional or attitude control is of good quality. Here, travel modulation sufficiently well meets an oncoming half-wave of the oscillating gear input rpm in order considerably to diminish or entirely extinguish the gear grabbing. A reproducible adjustment of travel modulation is a problem because the travel is measured in an incremental fashion and because the amplitude of a travel modulation amounts to only about 5 to 10 increments. In case of a clutch-grabbing oscillation period of 100 msec, a modulation takes 40 to 50 msec. During that short span of time, the attitude controller is called up 16 to 20 times. That includes compulsory controller call-ups within which the controller does not get to see any change in the actual travel. This means that the D-share [average share] of the controller becomes very rough, something that causes a deterioration in the quality of the controlling function and leads to unnecessary energy loss in the actuator.